There are a number of existing patents relating to rotating cylindrical flailing vegetation cutters:
U.S. Pat. No. 4,259,834 (Lambert et al 1981) entitled “Synchronized flail for treatment of forestry residues”;
U.S. Pat. No. 4,973,005 (Haesebrouck et al 1990) entitled “Hammer-crusher rotor”.
U.S. Pat. No. 5,003,759 (Brown 1991) entitled “Brush Mower”;
U.S. Pat. No. 5,485,718 (Dallman January 1996) entitled “Flail cutter and method of providing a flail cutter for a brush cutting machine”;
U.S. Pat. No. 5,570,571 (Dallman November 1996) entitled “Blade for a flail type brush cutting machine”;
U.S. Pat. No. 5,848,627 (Brown 1998) entitled “Rotor for land clearing device”;
U.S. Pat. No. 6,000,205 (Joray 1999) entitled “Flail-type vegetation cutter”;
U.S. Pat. No. 6,484,811 (Edwards 2002) entitled “Mulching unit for use in mulching apparatus”; and
U.S. Pat. No. 6,802,176 (Gaudreault 2004) entitled “Cutter head assembly”.